In a cell biology laboratory experiment, two students independently isolated the enzyme lactate dehydrogenase, which catalyzes the reduction of pyruvate to lactate, from chicken heart. The enzyme was obtained in the form of a concentrated solution. The students then measured the activity of their own enzyme solution as a function of substrate concentration under identical conditions and from the data determined the Vmax and KM of their own preparation. When they compared results, they noticed that their values of KM were identical, but their values of Vmax were radically different.One student argued that the different Vmax values confirmed thatthey had isolated different forms of the same enzyme. The otherstudent argued that, in spite of different Vmax values, they hadisolated the same form of the enzyme.
(a) Which student was correct? Why?
(b) How might they resolve the discrepancy?